Investing on some exchange? You mean you want to invest in exchange then you buy an altcoin? Can you clarify this,  i cant understand what you pointining is. But i think its ganna make sense if i suggest an exchange sites,  try hitbtc, bittrex and poloniex if you want to make a trade activity.  These are the most trusted exchange sites for me to use on some of my investment to make profits by buying some altcoin.